Device and fireproof nozzle for the injection and/or casting of liquid metals

ABSTRACT

In a process for splashing and/or teeming liquid metal, in particular steel, through a discharge in the wall or in the bottom of a metallurgical vessel, the discharge is electromagnetically coupled to the electromagnetic field of at least one fluid-cooled, in particular air-cooled, inductor. The inductor and the discharge are at least partially disposed in the wall or in the bottom of the metallurgical vessel. For teeming, the electromagnetic field of the inductor, or of the inductors, is coupled directly to the discharge and also the liquid metal. For this purpose, the frequency of the electromagnetic field or the electromagnetic fields, if appropriate, is adjusted correspondingly.

This application is a national stage of PCT/EP97/03695, filed Jul. 11,1997.

BACKGROUND OF THE INVENTION

The invention relates to a process for splashing and/or teeming ofliquid metals, in particular steel, through a discharge in the wall orin the bottom of a metallurgical vessel, wherein the discharge iselectromagnetically coupled to the electromagnetic field of at least onefluid-cooled inductor. The inductor and the discharge are disposed atleast partially in the wall or in the bottom of the metallurgicalvessel. Following splashing, the electric power of the inductor or theinductors, if appropriate, is changeable.

Such process for an inductor is disclosed in De 44 28 297 A1 in afree-running nozzle. In DE 41 36 066 A1 a discharge device for ametallurgical vessel is described, in which a cooled inductor isdisposed outside of the bottom of a vessel. In DE-A-24 33 582 anarrangement for the production of cast parts is disclosed, whereinseveral inductors, disposed one next to the other and switchableindependently of one another, are provided and which are cooled eitherwith water or with air. DE-AS 1 049 547 discloses an arrangement for theelectrically controlled teeming of metals. Below, and thus outside, ofthe bottom of a metallurgical vessel three coils are disposed asinductors laterally of a discharge. The coils are intended to generatein the steel column an alternating traveling field advancing from belowtoward the top, through which in the steel column, i.e. the outflowingmelt, an upwardly directed force component is generated, which,depending on the field strength, can decelerate or cancel the outflowingof the liquid steel. The metal column, rigid at the beginning ofcasting, can be inductively melted by the alternating field. In thetechnical work “Metallurgie des Stranggieβens”, {metallurgy ofcontinuous casting}, Editor: K. Schwerdtfeger, Publisher: Stahl-Eisen,Dusseldorf, 1992, pp. 449, electromagnetic agitation during continuouscasting and associated inductors are explained. Agitators are alwaysdisposed within the region of the strand-forming chill or, in thedirection of flow of the strand, behind it. A regulation and closingdevice for a metallurgical vessel with a rotor and a stator(pipe-in-pipe closing system) is described in DE 195 00 012 A1.Depending on the selection of the material for the rotor, either therotor itself or the melt flowing through it is coupled to theelectromagnetic field of an inductor.

In the case of horizontal continuous casting machines, the pouringdischarge or pouring discharges mount into a side wall of the meltvessel. The pouring discharge or pouring discharges is/are flanged ontoa chill such that the melt flows horizontally through the pouringdischarge, or the pouring discharges, into the chill. According to priorart, the pouring discharges before splashing are heated with a gasburner in order to prevent the freezing of the melt already duringsplashing. Carrying out this preheating is problematic since it cannotbe maintained during the preparatory mounting processes and thus thetemperature of the pouring discharge decreases, leading to the pouringdischarge being frozen closed during splashing. In the case ofhorizontal continuous casting machines, by necessity a specifictemperature gradient is set up in the liquid metal in a distributor. Inthe liquid metal flowing through the pouring discharges, this leads toso-called temperature streaks or “black strips” and thus to a quality ofreduction the cast strand.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a process of the above typefor the improvement of splashing and/or teeming. It is furthermore anobject of the invention to provide a refractory discharge suitable forthis purpose and a suitable arrangement or assembly incorporating suchdischarge.

According to the invention the above objects are achieved by provisionof an air-cooled inductor for use according to the invention in thebottom or the wall of a metallurgical vessel. Through the inductiveheating of a discharge during splashing it is attained that duringsplashing the discharge or the pouring discharge does not receivethermal shock fractures and that the metal melt entering it does notfreeze and even, in case an interruption occurs in casting, does notfreeze or metal frozen in it melts again. The heating of the dischargeor of the pouring discharge by means of at least one inductor is madepossible by use therefor at least partially of a material capable ofbeing coupled to the electromagnetic field of the inductor. The pouringdischarge of an inductively coupling material can also entirely orpartially comprise in its passage an inner layer of a non-inductivelycoupling, wear-resistant material which is heated by thermal conductionand/or heat radiation. When using a pouring discharge of a non-couplingmaterial, it is encompassed by a susceptor coupled to theelectromagnetic field which outputs to the pouring discharge thermalenergy through thermal conduction and/or heat radiation.

After splashing, thus for teeming, the frequency of the electromagneticfield of the inductor or of the inductors can be adjusted in such a waythat the field penetrates the pouring discharge and, if appropriate,also the susceptor and now also couples electromagnetically at least theouter layer of the liquid metal itself to the field. Thus, a temperatureeffect of the steel flowing through the pouring discharge becomes moreeffective. If appropriate, the liquid metal strand in the region of thedischarge is coupled to a further electromagnetic filed which does notprimarily serve for heating but rather has different functions, forexample, an agitating function. It is thus coupled for the purpose ofsplashing, as long as no liquid metal flows through the discharge, to italone and does so with optimum power and frequency for an adjustment intime of the desired temperature of the discharge. For teeming, thefrequency and, if necessary, also the power of the inductor is adjustedsuch that the liquid metal flowing through the discharge is also exposedto the electromagnetic field. The power can normally be reduced untilthe customary temperature losses in the discharge system arecompensated. However, it is also possible, in particular toward the endof teeming, to avoid freezing of liquid metal in the pouring discharge.Thereby, the discharge and/or the liquid metal flowing through thedischarge, is inductively heated by means of the inductor, for thepurpose of which the power of the inductor is successively increased.The potentially existing necessity of power matching depends on theinducting thermal energy, desired for reasons of process engineering,for heating or the desired movement in the steel flowing through thedischarge for the purpose of making the temperature uniform.

As indicated earlier, spatially changeable magnetic fields can begenerated in the liquid metal, and lead to motion in the liquid metalflowing through the pouring discharge. Such magnetic fields are realizedas rotary and/or linear traveling fields which generate in the liquidmetal in the discharge an agitation effect, similar to that described inthe earlier cited technical work, resulting in the temperature in thethroughflow cross section of the liquid metal becoming uniform such thattemperature streaks do not occur in the steel during its entrance intothe chill. Thereby, “black stripes” are avoided, leading to a qualityimprovement of the strand. The frequencies and/or powers required forthis purpose differ from those of heating inductors.

The process solves not only preheating problems or cooling problemsexisting before the melt outflow, but also temperature problems existingin the through-flowing melt itself. The process can readily be carriedout since for this purpose only the electromagnetic field of theinductor or of the inductors, in particular only is frequency and power,must be adjusted accordingly. The process can be used especiallyadvantageously in a horizontal continuous casting machine. However, itcan also be used in other installations.

During splashing and/or teeming, operation takes place at a firstfrequency between 2 kHz and 20 kHz, preferably between 6 kHz and 10 kHz.Operation preferably takes place during teeming at a further oradditional frequency, if appropriate in addition to the first frequency,between 3 Hz to 4000 Hz, preferably between 500 Hz to 3000 Hz. For thispurpose spatially variable electromagnetic fields are preferably usedfor generating an agitating effect, as will be explained later. In adevelopment of the invention, before and during splashing, operationtakes places at an electric power of 5 kW to 150 kW, preferably 30 kW to100 kW. During teeming, operation preferably takes place at aregulatable electric power between 3 kW and 120 kW, preferably 5 kW to40 kW. Thus, during teeming in many cases a lower electric powersuffices than during splashing, since potentially only temperaturelosses, for example through heat dissipation into the wall or the bottomof the metallurgical vessel or through heat radiation into theenvironment, must be compensated. Due to the regulatability of theelectric power, adaptation to the particular temperature conditions inthe melt is possible.

In a further development of the invention, an outflow of the dischargeis closed before splashing by means of a control element, known per se,for example a pipe-in-pipe closing system or a gate valve, and thedischarge, before filling the vessel with liquid metal, is heated bymeans of the inductor or one or several inductors, to a temperature atwhich the liquid metal within or in the region of the discharge does notfreeze such that the liquid metal flows out when the control element isopened. During teeming the discharge, in spite of heat radiation andcooling of the metal in the metallurgical vessel, can be maintained orbrought to temperatures which make difficult or prevent depositions offreezing melt or clogging.

If necessary, following filling of the vessel and of the discharge withliquid metal, the electric power and/or frequency of the inductor or oneor several inductors is adjusted such that the electromagnetic field ofthe inductor or of one or several inductors not only becomes coupled tothe discharge but also to the liquid metal. In this way, the metal iskept liquid in the discharge until the opening of the control element.Furthermore, by this measure a higher maximum energy can be introducedinto the discharge/metal system.

A refractory, inductively heatable discharge to be disposed at least tosome extent in the wall or in the bottom of a metallurgical vessel, inparticular for liquid steel, for carrying out the above process ispreheatable by means of at least one inductor, preferably air-cooled,also disposed in the wall or in the bottom of the metallurgical vessel.The wall thickness of the discharge and the frequency of theelectromagnetic filed of the inductor are matched to each other suchthat the electromagnetic field substantially penetrates the dischargewall, thus, extends substantially through the entire wall thickness ofthe discharge wall, and that during teeming of the liquid steel, ifappropriate, the electromagnetic field beyond the wall thickness of thedischarge is also coupled to the liquid steel, whereby the maximum powerconsumption of the system can again be increased.

The refractory discharge comprises preferably an inductively couplable,in particular refractory, ceramic material. The discharge can comprisean inner layer which comprises a relatively wear-resistant, potentiallynot inductively couplable material, as is described in DE 44 28 297 A1.The refractory discharge is preferably a pouring discharge which can,for example, also be integrated with a immersion discharge, and which,if appropriate, can be set into a refractory sleeve which, ifappropriate, comprises an inductor as a structural unit. The pouringdischarge comprised of inductively couplable ceramic, is preferablyproduced of a carbon-bound material with a high alumina content,potentially with a wear-resistant inner layer or outer layer comprising,for example, zirconium oxide. To improve flow conditions, the pouringdischarge can be widened in the shape of a diffuser in the inflow and/oroutflow region. In particular in the outflow region, at least inhorizontal continuous casting, widening is advantageous if the melt ispoured in the near liquid state.

An arrangement or assembly for splashing and teeming of liquid metals,in particular steel, with a discharge which is disposed at least to someextent in the wall or in the bottom of a metallurgical vessel, and withat least to some extent in the wall or in the bottom of a metallurgicalvessel, and with at least one inductor for carrying out the aboveprocess includes an inductor that is, at least to some extent,air-cooled and is provided with one or several fluid-cooled coolingcirculations. The power and/or the frequency of the electromagneticfield of the inductor or of the inductors can be adjusted as a functionof the casting conditions by at least one frequency changer orconverter. It is therein conceivable that, for example, one inductor iswater-cooled and the other is air-cooled, or that one inductor haswater-cooling circulation and one has an air-cooling mechanism. Thearrangement for splashing and/or teeming of liquid steel comprisespreferably one inductor for generating electromagnetic rotary fieldsand/or linear traveling fields in the liquid steel strand in the regionof the discharge. The rotary fields and/or the traveling fields can bedisposed one behind the other in the direction of flow of the liquidmetal or they can be superimposed. They serve for generating the abovediscussed agitation effect, in particular for making uniform thetemperature of the metal strand in the discharge. A further inductor canserve for heating the discharge and the strand in the region of thedischarge. The powers and/or frequencies of the particular inductorsdiffer according to their purpose.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantageous features of the invention are described in thefollowing description of embodiments thereof. In the drawings:

FIG. 1 is a sectional view of a discharge and an arrangement forsplashing and teeming in a melt vessel with an attached chill supportingone or several pouring discharges of a horizontal continuous castingmachine;

FIG. 2 is a corresponding view of a discharge, however with twoseparately controllable inductors; and

FIG. 3 is a sectional view of a pipe-in-pipe closing system with aninductively heated stator in the bottom of a melt vessel.

DETAILED DESCRIPTION OF THE INVENTION

According to FIGS. 1 and 2, in a side wall I of a vessel, specifically ametallurgical vessel, whose inner volume is denoted by 2, an inductor 4is disposed in a refractory sleeve 3. The inductor 4 is cooled with air,at least to some extent, via pipe lines 13 and is electrically connectedto a frequency changer of converter 5 whose frequency F and whoseelectric power L are adjustable. The inductor 4 is produced of ahelically formed copper pipe. It is disposed about an intermediatesleeve 6 which serves for temperature insulation and for introducingpouring discharge 9, described in further detail below, into the openingof the side wall 1 of the vessel.

To a chill 7, associated with the vessel, is exchangeably flanged bymeans of a securing device 8 pouring discharge 9. In FIGS. 1 and 2 apouring discharge is depicted. Further pouring discharges, flanged inthe same way to the chill 7, are, if appropriate, disposed behind theplane of the drawing. In the representation according to FIGS. 1 and 2,pouring discharges 9, supported by the chill 7, are slid into theintermediate sleeve 6 by horizontal movements of the chill 7. A cementlayer 10 serves for sealing between the pouring discharge 9 andintermediate sleeve 6. The pouring discharge 9, representing a wearpart, comprises carbon-bound ceramic material containing alumina, whichbecomes inductively coupled to an electromagnetic field of inductor 4.The pouring discharge 9 forms a throughflow cross section 11 for steelmelt flowing from the inner volume 2 of the vessel into the chill 7. Thethroughflow takes place in the horizontal direction H.

Operation is substantially as follows:

At the latest after the chill 7 with the pouring discharge(s) 7 isbrought into the position shown in FIGS. 1 and 2 with the inner volume 2of the vessel still empty, the inductor 4 is switched on by means of thechanger or converter 5. By means of the frequency changer or converter5, a frequency and an electric power are adjusted which, for thepurposes of splashing, brings the pouring discharge 9 at least to atemperature, and maintains it at that temperature, at which theinflowing melt does not freeze. The inductive heating can also, and inparticular further, be operated if a gas heating, potentially carriedout in advance, of the vessel must be switched off the vessel is movedinto the casting position in front of the chill. In the castingposition, the metal melt S is filled into the inner volume 2 of thevessel. The melt flows through the pouring discharge 9 into the chill 7from which it is drawn off as a solidified strand.

For heating the pouring discharge 9 before the splashing step, thefrequency and/or the power of the electromagnetic filed of inductor 4can be adjusted by means of the changer 5 to be higher than during afollowing teeming operation, described later. The frequency of theelectromagnetic field is adjusted for the heating of the pouringdischarge 9 such that the depth of penetration of the electromagneticfield covers substantially the wall thickness 12 of the pouringdischarge 9. The electric power of the changer 5 is regulated accordingto a predetermined heating time. Before and during the splashing, theoperation takes place at a frequency between 2 kHz and 10 kHz,preferably between 4 kHz and 10 kHz, and an electric power of 5 kW to150 kW, preferably 20 kW to 60 kW. The depth of penetration of theelectromagnetic field is to be 10 mm to 300 mm, preferably 10 mm to 40mm, corresponding to the wall thickness 12 of the pouring discharge 9.After splashing, i.e. after the initial inflow of the melt through thedischarge into the chill, and during subsequent teeming, the frequencyof the changer 5, and thus that of the electromagnetic field of theinductor 4, is adjusted such that the electromagnetic field penetratesthrough the wall thickness 12 of the pouring discharge 9 into the metalmelt flowing through the throughflow cross section 11. In the extremecase the penetration depth into the liquid steel can be up toapproximately 100 mm. Conventionally operation takes place at afrequency between 6 kHz and 10 kHz. During teeming, apart from theconventional heating frequency, operation can take place with a furtherfrequency between 3 Hz and 4000 Hz, preferably between 500 Hz and 3000Hz in order to make uniform the temperature of the molten steel in thedischarge. During teeming the electric heating power can be reduced. Inthis case it is between 3 kW and 120 kW, preferably between 5 kW and 40kW. By adjusting the electric power before and during splashing, thetemperature of the pouring discharge 9, and during teeming also thetemperature of the through-flowing melt, can be influenced with a powerincrease causing in each instance a temperature increase.

In the event of a casting interruption, metal, possibly rigidified inthe pouring discharge 9, can be rendered molten again and the strandagain can be started. Through the specific inductive coupling of thethrough-flowing melt to the field of inductor 4, it is not only attainedthat the temperature of the melt can be effected. Through such inductivecoupling, eddy currents are generated in the melt, which move thethrough-flowing metal melt in the throughflow cross section 11, suchthat substantially a uniform temperature distribution is present in themelt in the throughflow cross section 11. Thus, no temperature gradientoccurs in the flowing metal melt, or temperature variations in thethrough-flowing metal melt from a temperature gradient in thedistributor are compensated. This agitation effect can be improved sinceby means of inductor 4, or several inductors, a spatially changingmagnetic field, for example, a rotary field and/or traveling field, isgenerated in the melt within the throughflow cross section 11. For thispurpose the inductor 4 or the inductors are driven correspondingly bythe changer 5 or several changers. Through such agitation metallicand/or nonmetallic depositions in the discharge or in the region of thedischarge can also be prevented or eliminated. FIG. 2 shows an exampleof two inductors separately drivable by changers 5 and 16.

Toward the end of teeming, i.e. after the inner volume 2 of vessel 1gradually empties, the frequency and/or the power of changer 5, and thusof inductor 4, can be adjusted such that during heating of the pouringdischarge 9 and/or of the outflowing remainder of the melt, the latterdoes not freeze. The pouring discharge 9 can also be provided with aninner layer which is more wear-resistant with respect to the melt thanthe material of the pouring discharge. In the region of the melt entryand/or the melt exit the pouring discharge 9 can be widened in the formof a diffusor or conically to improve the flow.

In another embodiment in which the pouring discharge 9 itself is notcoupled to the electromagnetic field of inductor 4, for heating thepouring discharge 9 a susceptor can be provided which is heatedinductively by inductor 4. Such susceptor can, for example, be disposedbetween the intermediate sleeve 6 and the pouring discharge 9 or also bea component of the pouring discharge 9 in the form of another jacket(not shown). Such susceptor subsequently transfers indirectly the heatfor splashing by thermal conduction and/or heat radiation to the pouringdischarge 9.

FIG. 3 shows an example of a further embodiment of the invention, inwhich at the side of outflow of the melt is provided a control element,known per se, for example a pipe-in-pipe closing system 15. In this casethe pouring discharge is in the form of a stator 14 and can be disposedin the bottom of the metallurgical vessel such that the melt flows outvertically. It is also possible that the discharge or the stator 14 isrealized in the form of an immersion discharge, and thus comprises anextension downwardly into the chill (not shown). Before splashing, thecontrol element is closed and the stator 14 is heated by means ofinductor 4 to a temperature at which the melt in the discharge cannotfreeze during splashing. After melt has been filled into the vessel, thecontrol element is opened so that the melt, without freezing in thedischarge, flows out. Following the filling of the vessel and afteropening of the pipe-in-pipe closing system 15, the electric power and/orfrequency of inductor 4 can be adjusted such that the electromagneticfield of inductor 4 is not only coupled to the discharge but also to themelt so that the latter is kept in a flowable state before the meltflows out. This is also, and in particular, of advantage for thesplashing of a gate-valve closure, know per se, in which, before thevessel is filled, the melt arrives in the outflow up to a closing plateand freezes there if special measures, such as sand filling, are nottaken. If, in contrast, according to the invention, the melt in thedischarge is kept liquid, sand filling or the like can be omitted. Also,during teeming in the stator 14, the steel can be agitated as well asalso be heated electromagnetically which permits low teemingtemperatures.

What is claimed is:
 1. A process for splashing and teeming molten metalthrough a discharge in a wall or a bottom of a metallurgical vessel,said process comprising: before and during said splashing and duringsaid teeming of said molten metal through said discharge,electromagnetically coupling said discharge to an electromagnetic fieldof at least one inductor that is at least to some extent disposed insaid wall or said bottom of the metallurgical vessel, while at leastpartially air-cooling said at least one inductor; during said splashing,adjusting at least the frequency of said at least one inductor such thatsaid electromagnetic field penetrates substantially the wall thicknessof said discharge; and during said teeming, adjusting at least thefrequency of said at least one inductor such that said electromagneticfield penetrates beyond said wall thickness of said discharge and intosaid molten metal flowing through said discharge.
 2. A process asclaimed in claim 1, wherein said frequency during said splashing isadjusted to 2 kHz to 10 kHz.
 3. A process as claimed in claim 1, whereinsaid frequency during said splashing is adjusted to 4 kHz to 10 kHz. 4.A process as claimed in claim 1, wherein said adjusting during saidsplashing comprises also adjusting the power of said at least oneinductor.
 5. A process as claimed in claim 4, wherein said power duringsaid splashing is adjusted to 5 kW to 150 kW.
 6. A process as claimed inclaim 4, wherein said power during said splashing is adjusted to 20 kWto 60 kW.
 7. A process as claimed in claim 1, wherein said frequencyduring said teeming is adjusted to 6 kHz to 10 kHz.
 8. A process asclaimed in claim 1, further comprising, during said teeming,electromagnetically coupling said molten metal to a furtherelectromagnetic field.
 9. A process as claimed in claim 8, furthercomprising adjusting the frequency of said further electromagnetic fieldto 3 Hz to 4000 Hz.
 10. A process as claimed in claim 8, furthercomprising adjusting the frequency of said further electromagnetic fieldto 500 Hz to 3000 Hz.
 11. A process as claimed in claim 1, wherein saidadjusting during said teeming comprises also adjusting the power of saidat least one inductor.
 12. A process as claimed in claim 11, whereinsaid power during said teeming is adjusted to 3 kW to 120 kW.
 13. Aprocess as claimed in claim 11, wherein said power during said teemingis adjusted to 5 kW to 40 kW.
 14. A process as claimed in claim 11,wherein said power is adjusted to be higher during said splashing thanduring said teeming.
 15. A process as claimed in claim 1, comprisingentirely air cooling said at least one inductor during said splashingand said teeming.
 16. A process as claimed in claim 1, comprisingconducting said teeming at plural independent frequencies.
 17. A processas claimed in claim 1, comprising conducting said teeming at pluralindependent electric powers.
 18. A process as claimed in claim 1,further comprising, during said teeming, coupling at least one spatiallyvariable electromagnetic field to said molten metal flowing through saiddischarge.
 19. A process as claimed in claim 1, wherein outflow of saidmolten metal from said discharge is controlled by a closing system, andfurther comprising, prior to filling of said molten metal into saidmetallurgical vessel, operating said closing system to close saiddischarge, and said electromagnetically coupling comprises heating saiddischarge to a temperature sufficient to, upon subsequent filling ofsaid molten metal into said metallurgical vessel and operating saidclosing system to open said discharge, prevent said molten metal fromfreezing in said discharge.
 20. A process as claimed in claim 19,further comprising, upon said operating said closing system to open saiddischarge, electromagnetically coupling said molten metal flowingthrough said discharge to an electromagnetic field.
 21. A process forsplashing and teeming molten metal through a discharge in a wall or abottom of a metallurgical vessel, said process comprising: before andduring said splashing and during said teeming of said molten metalthrough said discharge, electromagnetically coupling said discharge toan electromagnetic field of at least one inductor that is at least tosome extent disposed in said wall or said bottom of the metallurgicalvessel, while at least partially air-cooling said at least one inductor;and conducting said teeming at plural independent frequencies and/orplural independent electric powers.
 22. A process as claimed in claim21, comprising adjusting a frequency of said inductor during saidsplashing to 2 kHz to 10 kHz.
 23. A process as claimed in claim 21,comprising adjusting a frequency of said inductor during said splashingto 4 kHz to 10 kHz.
 24. A process as claimed in claim 21, comprisingadjusting a power of said inductor during said splashing.
 25. A processas claimed in claim 24, wherein said power during said splashing isadjusted to 5 kW to 150 kW.
 26. A process as claimed in claim 24,wherein said power during said splashing is adjusted to 20 kW to 60 kW.27. A process as claimed in claim 21, comprising adjusting a frequencyof said inductor during said teeming to 6 kHz to 10 kHz.
 28. A processas claimed in claim 21, comprising, during said teeming,electromagnetically coupling said molten metal to a furtherelectromagnetic field.
 29. A process as claimed in claim 28, furthercomprising adjusting the frequency of said further electromagnetic fieldto 3 Hz to 4000 Hz.
 30. A process as claimed in claim 28, furthercomprising adjusting the frequency of said further electromagnetic fieldto 500 Hz to 3000 Hz.
 31. A process as claimed in claim 21, comprising,during said teeming, adjusting said electric power of said at least oneinductor.
 32. A process as claimed in claim 31, wherein said powerduring said teeming is adjusted to 3 kW to 120 kW.
 33. A process asclaimed in claim 31, wherein said power during said teeming is adjustedto 5 kW to 40 kW.
 34. A process as claimed in claim 31, wherein saidpower is adjusted to be higher during said splashing than during saidteeming.
 35. A process as claimed in claim 21, comprising entirely aircooling said at least one inductor during said splashing and saidteeming.
 36. A process as claimed in claim 21, comprising conductingsaid teeming at plural independent frequencies.
 37. A process as claimedin claim 21, comprising conducting said teeming at plural independentelectric powers.
 38. A process as claimed in claim 21, furthercomprising, during said teeming, coupling at least one spatiallyvariable electromagnetic field to said molten metal flowing through saiddischarge.
 39. A process as claimed in claim 21, wherein outflow of saidmolten metal from said discharge is controlled by a closing system, andfurther comprising, prior to filling of said molten metal into saidmetallurgical vessel, operating said closing system to close saiddischarge, and said electromagnetically coupling comprises heating saiddischarge to a temperature sufficient to, upon subsequent filling ofsaid molten metal into said metallurgical vessel and operating saidclosing system to open said discharge, prevent said molten metal fromfreezing in said discharge.
 40. A process as claimed in claim 39,further comprising, upon said operating said closing system to open saiddischarge, electromagnetically coupling said molten metal flowingthrough said discharge to an electromagnetic field.
 41. An arrangementfor splashing and teeming molten metal, said arrangement comprising: ametallurgical vessel for containing molten metal; a discharge, disposedin a wall or a bottom of said metallurgical vessel, for splashing andteeming molten metal therefrom; a first inductor, disposed at least tosome extent in said wall or said bottom of said metallurgical vessel,for generating a spatially variable first electromagnetic field to becoupled to molten metal in said discharge; a second inductor, disposedat least to some extent in said wall or said bottom of saidmetallurgical vessel, for generating a second electromagnetic field,independent of said first electromagnetic field, to be coupled to saiddischarge to heat said discharge and to maintain heated said dischargeand molten metal therein; said first and second inductors being operableindependently at respective frequencies and electric powers; and atleast one of said inductors being at least partially air-cooled.
 42. Anarrangement as claimed in claim 41, wherein said at least one of saidinductors is entirely air-cooled.
 43. An arrangement as claimed in claim41, wherein both said first and said second inductors are at leastpartially air-cooled.
 44. An arrangement as claimed in claim 41, whereinsaid first and second inductors are entirely air-cooled.
 45. Anarrangement as claimed in claim 41, wherein said discharge comprises arefractory sleeve.
 46. An arrangement as claimed in claim 45, wherein atleast one of said inductors is embedded in said sleeve.
 47. Anarrangement as claimed in claim 45, wherein both of said first and saidsecond inductors are embedded in said sleeve.
 48. An arrangement asclaimed in claim 45, wherein said sleeve is widened in at least one ofan inflow region and an outflow region thereof.
 49. An arrangement asclaimed in claim 45, wherein said sleeve has applied to an inner surfacethereof a layer of wear resistant material.
 50. An arrangement asclaimed in claim 41, further comprising respective converterselectrically connected to said inductors for adjusting said respectivefrequencies and electric powers.
 51. An arrangement as claimed in claim41, further comprising a closing system for opening and closing apassage through said discharge.
 52. A refractory discharge to bedisposed in a wall or a bottom of a metallurgical vessel for splashingand teeming molten metal from said metallurgical vessel, said dischargecomprising: a flowthrough passage through said discharge; a firstinductor, to be disposed at least to some extent in the wall or thebottom of the metallurgical vessel, for generating a spatially variablefirst electromagnetic field to be coupled to molten metal in saiddischarge; a second inductor, to be disposed at least to some extent inthe wall or the bottom of the metallurgical vessel, for generating asecond electromagnetic field, independent of said first electromagneticfield, to be coupled to said discharge to heat said discharge and tomaintain heated said discharge and molten metal therein; said first andsecond inductors being operable independently at respective frequenciesand electric powers; and at least one of said inductors being at leastpartially air-cooled.
 53. A discharge as claimed in claim 52, said atleast one of said inductors is entirely air-cooled.
 54. A discharge asclaimed in claim 52, wherein both said first and said second inductorsare at least partially air-cooled.
 55. A discharge as claimed in claim52, wherein said first and second inductors are entirely air-cooled. 56.A discharge as claimed in claim 52, comprising a refractory sleeve. 57.A discharge as claimed in claim 56, wherein at least one of saidinductors is embedded in said sleeve.
 58. A discharge as claimed inclaim 56, wherein both of said first and said second inductors areembedded in said sleeve.
 59. A discharge as claimed in claim 56, whereinsaid sleeve is widened in at least one of an inflow region and anoutflow region thereof.
 60. A discharge as claimed in claim 56, whereinsaid sleeve has applied to an inner surface thereof a layer of wearresistant material.
 61. A discharge as claimed in claim 52, furthercomprising respective converters electrically connected to saidinductors for adjusting said respective frequencies and electric powers.